Hi All.
I need some advice. We had to take a drive from Asheville to Charlotte. The AC was fine on the way there. On the way back it stopped blowing cold air. We sat in the airport cell phone lot for about an hour with the AC running. It was about 95 degrees out. I can hear the fan blowing but virtually no air is coming out. The little bit that is coming out isn't cold. The following day all was working again. I took it to my dealer and of course, they couldn't find any issues. Any suggestions? 2018 XC 60 T5.
As always, thanks for any input.

 

sometimes the evaporator in the dash can ice up which will restrict airflow even through the AC is running. Turn the AC off for about 10 minutes the ice melts and bada-bing, you have cold again. The other possible cause for an AC that quits but returns after a cool down is when the AC clutch gap is too large. This is common to older cars but I wouldn't suspect a clutch issue on a 2018. To note on the evaporator ice up, there are two things the shop can do for you: 1) make sure the evaporator drain ports are clean so any water can drain out quickly 2) check the AC for a proper charge level. Its possible your car can have a slight overcharge condition that can be corrected by the shop to bring it back into spec.

 

There are been many reports of your same problem. It is caused by the evaporator freezing up because the refrigerant is too cold. The condensation that naturally forms when the ac is on is too cold and freezes on the fins rather than draining off. Eventually the evaporator fills with "frost" and blocks the flow of air. Perhaps the evaporator temp sensor is not working properly (turning the compressor off when the temp is too cold) or I had heard rumors of a software update that Volvo was doing to solve the problem.

 

The ac has stopped working. I have checked both fuses in the block in cabin, and checked and cleaned the connector to the compressor. The low side pressure was at 150 psi which I know is high because the compressor is not engaging. I'm thinking it may be the magnetic compressor clutch. I wanted to get some feedback on whether or not there is anything else I need to check before I start replacing parts.

 

There are many things that will keep power from getting to the compressor clutch. Temp and pressure sensors are some. A good first step would be using a compatible scanner on all of the control units. First to check for codes and then you can view live readings of sensor signals.
A good scan tool can usually activate the ac clutch manually also.

 

I would say check to see if you have power going to the clutch. If you do, and it's not on, then your first assumption might be the air gap is too high. If you don't, then of course you have to troubleshoot. You can also jumper power to the clutch.

On the older cars, there used to be some argument that the relay got worse over time and voltage to the clutch would be low.